Stabilization of polymer-alkali metal mercaptides

ABSTRACT

Polymers having at least one terminal alkali metal mercaptide end group per molecule are converted to products having improved oxidative stability by reaction with metal halides of Group 4a of the Periodic Table.

United States Patent Uraneck et al.

[54] STABILIZATION OF POLYMER- ALKALI METAL MERCAPTIDES [72] Inventors: Carl A. Uraneck; William J. Trepka, both of Bartlesville, Okla.

[73] Assignce: Phillips Petroleum Company [22] Filed: July 2, 1970 2| Appl. No.: 52,140

[52] U.S. Cl. ..260/79, 260/45.75 R, 260/45.75 K, 260/94.7 HA, 260/94.7 S [51] Int. Cl ..C08g 23/00 [58] Field of Search ..260/79, 94.7, 94.7 S, 45.75, 260/45.75 K

[56] References Cited UNITED STATES PATENTS 3,048,568 8/1962 Cleary ..260/79 [451 July 4, 1972 3,3l7,46l 5/1967 Plueddemann ..260/46.5

OTHER PUBLICATIONS Sanderson, Chemical Periodicity, Reinhold Publ. Co., N.Y., l960,pg. 83

Primary Examiner-Donald E. Czaja Assistant Examiner-M. l. Marquis AtlurneyYoung and Quigg [5 7] ABSTRACT Polymers having at least one terminal alkali metal mercaptide end group per molecule are converted to products having im proved oxidative stability by reaction with metal halides of Group 4a of the Periodic Table.

6 Claims, No Drawings trihexyl iodotin, tricyclohexyl bromogermanium, trimethyl chlorolead, diphenyl dichlorosilane, l,l-dichlorosilacyclohexane and l, l-dichloro stannacycloctane.

The quantity of the reactant represented by formula R,.MX,,

In one of its more specific aspects, this invention relates to 5 hi h i l d i i h range f f o about 1 to about 5 foltmafion of table Polymer alkali metal mercaptide preferably from about 1.5 to 3, milliequivalents per mildenvanve f liequivalent of alkali metal employed in the polymerization iny f f p y alkali meial'based lmtlators, itiator. One mole of the R,,MX,, compound contains a gram such as lithium compounds, is well known. Generally, the equivalent f eachxin the mohacu]epolymers of greatest interest are derived from monomers such T method f this invention is cal-dad out by mixing the as conjugatefj l f and monovinyl aromatic compoundsreactants, optionally in the presence of an inert hydrocarbon The polymerization is usually conducted in an inert hydrocardiluent, f bl a polar compound, and bringing h 9" dlluen? to P P y containing at 0m perature of the reactants within the range of from about 0 C. alkal' metal end groupto about 200 C., preferably from about 50 C. to about 100 also know to cfmven these Polymers Polymcrs C., under any suitable pressure for a period from about 1 having at least one terminal alkali metal mercaptide end group minute to about 100 hours or longer The resulting product per f f In ger'leral thls done by reatmg the Polymer can be produced in a solution in which form it can be handled comamm? ten-mm} alkah mfetal group sfllfur f with decreased likelihood of mercaptide oxidation, or in an organic disulfide. The alkali metal mercaptide ten-ninal which solution it can he treated to hydrolyze the mercaptide 'z izz produced can be hydrolyzed to produce a mercaptan groups without excessive loss of the mercaptide group by the en 3 side reaction of oxidation.

, Those polymers having the alkali metal mercaptide terminal The method of this invention was carried out employing a group are frequently intermediate compounds. As interpolymehalkah metal mercaptide which had been formed by mediates, they are sub ected to considerable handling. polymerizing g of llhmadiene in the presence of 015 Because these compounds can become useless if oxidized, exmhhmoles of n hmylhmimn at in 120 m1 cyclohexane pensive procedural steps must employed to prevent their for 075 hours, after which the resulting polymer product was Premature Contact 4 jh reacted with 1,8-naphthylene disulfide at 27 C. for a period of cordmgly, a method of converting these easily oxidized alkali about 3 to 5 minutes to produce the polymehalkah metal m e metal mercapude forms to ,less easlly oxidized 30 captide. Two samples of the polymer-alkali metal mercaptide forms would be of considerable value in the processing of were recovered and each was analyzed by an amperometric polymers. The method of this invention provides such a titration, with AgNOa as the tram. w determine its mercap process tan concentration.

Accordmg to the i q of this Invention f 15 provlded The first ofthese samples was reacted with 0.04 moles silzipmcess. for he stablhzauon of poiymepalkah metal Him-capicon tetrachloride at a temperature of 50 C. for about onetides which involves the conversion of the mercapt des to half hour for the purpose of Stabilizing the polymer alkah Group 4a metal derivatives which comprises reacting the metal mercaptide against oxidation. The second sample as polymer-alkali .metal mercaptide with a metal halide having not treated by the method ofthis invention the general formula Each sam le was then stirred with iso to 1 alcohol and air Also, according to this invention, there is provided a Group bl d d d p h 1 4a metal derivative of an alkali metal mercaptide polymer. i an agnate i un Cr n la y 1 en conitions. Analyses were again made, as before, of each sample The method of thls Invention ls apphcable to polymers to determine its merca tan concentration Results were as folcontaining at least one alkali metal mercaptide group. lows p Preferably, the polymer will have been prepared by initiating its formation from one or more monomers with an organoal kali metal compound in an inert hydrocarbon diluent and will fig g gz f 2535 n XZ'STS'E 1: :23: contain, at this stage, at least one terminal alkali metal end group, preferably lithium.

The resulting product will have been preferably reacted 5 8' X 104 X l0 1 58 X 10 with sulfur or with suitable sulfur compounds, such as organic 5Q disulfides, to form the alkali metal mercaptide terminal group.

F r this conversion, 1,8-na hth lene disulfide is advgmageously employe p y The above data illustrate the operability of the method of The Suitable meta] halides can b represented by the this invention and its effectiveness in stabilizing polymer-alkali general f l RaMxb in hi metal mercaptides against oxidation.

M is silicon or a metal of Group 4a of the Periodic Table data mdlcate that about 99 percent of the g y- (Handbook of Chemistry and Physics, 46th Edit, pg. B3, dFtmlinable f p f was Oxidized and P destroyed i Chemical Rubber Co., Cleveland, Ohio, 1964), and includes t ll m s: whlclhwaslnot trsatedhin accordarice lwith silicon, ermanium, tin and lead; 2 me o o is mven on. n con as owever, on y a ou R is a monovalent or divalent hydrocarbon radical contain- 6O 9 P nt Of th riginally-determinable mercaptan was oxing from one to about 20 carbon atoms and includes groups idized in that solution which had been stabilized in accordance such as the alk l, a l, c cloalk l and alk lene; with the method of this invention.

X isahaloggi'i; ry y y y The foregoing determinations of mercaptan content were and a and b are positive integers,the sum of which equals based upon a method which hydrolyzes the mercaptide to the the valence of M when R is a monovalent radical and 2a b mercaptan. Inasmuch as the content of mercaptan in the two being equal to the valence of M when R is a divalent radical, analyses for Sample No. 1 was substantially the same, the data the value of b being from 1 to 4; a can be zero. indicate that the reaction product of the silicon tetrachloride In the formula R,,MX,,, M is preferably tin or silicon and X is reaction is hydrolyzable to the mercaptan to substantially the preferably chlorine. same extent as the unstabilized polymer alkali metal mercap- Examples of suitable compounds complying with the above tide compound. formula are silicon tetrachloride, tin tetrachloride, germanium It will be evident from the foregoing that various modificatetrabromide, methyl trichlorosilane, eicosyl tribromotin, tions can be made to the method and to the product of the phenyl triiodogermanium, cyclohexyl trifluorolead, dimethyl method of this invention. Such, however, are considered as dichlorosilane, dibutyl dichlorotin, diphenyl dichlorogermariibeing within the skill of the art, um, di( l-naphthyhdibromolead, trimethyl chlorosilane, What is claimed is:

l. A method for the oxidative stabilization of a polymer prepared in the presence of an alkali-metal-based initiator and having at least one alkali metal mercaptide terminal group which comprises reacting said polymer with a halide having the fonnula R,,MX,,, said halide being employed in an amount within the range of from about 1 to about 5 milliequivalents per milliequivalent of the alkali metal of said initiator wherein:

R is a monovalent or divalent hydrocarbon radical containing from one to carbon atoms;

M is selected from the group consisting of silicon, gen'nanium, tin and lead;

X is a halogen;

a and b are integers, and a can be zero, and b has a value within the range of l to 4, the sum of a b being equal to the valence of M when R is a monovalent hydrocarbon radical and the sum of 20 b is equal to the valence of M when R is a divalent hydrocarbon radical to produce an oxidatively stable derivative of said polymer.

2. The method of claim 1 in which the reaction is conducted at a temperature within the range of from about 0 C. to about 200 C. in an inert diluent.

3. The method of claim 1 in which said polymer having at least one alkali metal mercaptide terminal group is prepared by the polymerization of at least one monomer, said polymerization being initiated with an organoalkali metal compound.

4. The method of claim 3 in which said halide is employed in an amount within the range of from about I to about 5 milliequivalents per milliequivalent of said organoalkali metal compound.

5. The method of claim 1 in which said halide is silicon tetrachloride.

6. The method of claim 1 in which said alkali metal mercaptide terminal group comprises lithium. 

2. The method of claim 1 in which the reaction is conducted at a temperature within the range of from about 0* C. to about 200* C. in an inert diluent.
 3. The method of claim 1 in which said polymer having at least one alkali metal mercaptide terminal group is prepared by the polymerization of at least one monomer, said polymerization being initiated with an organoalkali metal compound.
 4. The method of claim 3 in which said halide is employed in an amount within the range of from about 1 to about 5 milliequivalents per milliequivalent of said organoalkali metal compound.
 5. The method of claim 1 in which said halide is silicon tetrachloride.
 6. The method of claim 1 in which said alkali metal mercaptide terminal group comprises lithium. 